Houses and other buildings frequently have exterior clapboard walls for a desired aesthetic appearance, among other means. Since clapboard walls are made of wood planks, they must be periodically painted or replaced. To avoid such work and expense, it has become common practice to provide exterior siding of the same profile as clapboard but actually made of a plurality of assembled metallic painted panels.
Till now, these panels have been of a maximum width not exceeding two declinations, a declination being a flat, outwardly, downwardly-inclined rigid strip or sheet-intended to resemble a clapboard. A building wall is conventionally several horizontal rows of panels, by covered by nailing or otherwise securing each panel of a row along its upper edge and overlapping the side edges of two adjacent panels. The panels cannot be more than two declinations wide, because the central joint portions of two adjacent panels would tend to separate and/or bulge outwardly, which is ineffective and unsightly. Thus, it is time-consuming and costly to install two-declination panels, because more material must be used and less wall area is covered per unit panel, and because more man-hours are required.